This project explores the relationship between minor physical anomalies (MPAs) and Attention-deficit Hyperactivity Disorder (ADHD). These minor anomalies may be of major diagnostic significance, indicating general classes of altered morphogenesis or specific malformation syndromes. Many studies have reported an overrepresentation of MPAs in ADHD children. But a few anomalies have been investigated, and there have been difficulties in rendering their diagnosis objective and reliable. Using quantitative methods designed to overcome these diagnostic limitations, we will expand the catalog of MPAs available for study. These MPAs will be used to test hypotheses about the underlying biology of ADHD. Combinations of MPAs will be studied rather than individual anomalies, which are of limited theoretical interest. The study adopts three categories of combinations: (1) the full-scale MPA score. This measure, conventionally used in studies Of MPAs, sums across the anomalies in the protocol. The score will be used to determine whether ADHD patients are more generally dyamorphic than normal control children. (2) combinations of MPAs consistent with specific dysmorphological mechanisms. These measure will allow us to test whether discrete developmental processes have gone awry in ADHD. (3) malformation syndromes. We will use clustering techniques aimed at assigning ADHD patients into subgroups on the basis of their patterns of MPAs. We will complement these quantitative techniques with the clinical judgement of a dyamorphologist. He will screen patients for the presence of known genetic and teratogenic syndromes. We will use these techniques to determine whether ADHD dyamorphology can be resolved into more homogenous phenotypes.